Field of the Invention
The present invention relates to a double-sided transparent conductive film, and a touch panel.
Description of the Related Art
In recent years, projected-capacitive touch panels or matrix-type resistive touch panels can attain multi-point input (multi-touch) to be excellent in operability. Demands therefor have been rapidly increasing. As an electrode member of such a touch panel, a double-sided transparent conductive film is suggested, in which transparent conductive thin films are formed on both sides of a transparent film base material, respectively.
A touch panel as described above makes use of a double-sided transparent conductive film having patterned transparent conductive layers. As the material of the transparent conductive layers, indium/tin composite oxide (ITO) is widely used from the viewpoint of the visible ray transmittance thereof. However, the refractive index of ITO is high. Thus, when a transparent conductive layer containing ITO is patterned, a difference is generated in pattern-visibility between its part in which the transparent conductive layer constitutes the pattern (pattern-formed part) and its part in which the transparent conductive layer is removed (pattern opening part). Accordingly, when the pattern is observed from the outside, the touch panel may be deteriorated in appearance or a hue (color tone) may be generated. In order to make such a pattern inconspicuous, in a double-sided transparent conductive film having, on its both sides, transparent conductive layers, respectively, suggested is a technique of providing an optical adjusting layer between the film base material and the transparent conductive layer (WO 2011/065032).